Method of recovering well fluids



Filed Jan. 2, 1957 2 Sheets-Sheet l May 11, 1937. J. P. WALKER Er Al.

METHODOF RECOVERING WELL FLUIDS 2 Sheets-Sheet 2 Filed Jan. 2, 1937 30 mations.

Patented May 11,' 1937 Jay P. walker, Tulsa, okla., and Edwin v. Ecran,

San Antonio, Tex.

Application January z, 1937, serial No. 118,890

(ci. lss-114.6)

'I Claims.

This invention relates to new and useful improvements in methods of recovering well fluids. 'I'he invention has to do with the recovery of certain hydrocarbon fluids, usually produced or accumulated from the well streambr Well fluids in a more or less vaporous form, which when converted into a liquid phase, will have the characteristics of the native liquids normally present in the well fluids; and also whereby the residual gas may be utilized or disposed of in any suitable manner, or recovered at such pressures as to make for economical and efcient delivery to input wells for preserving reservoir pressure and minimizing precipitation within the reservoir, and

1;, for displacing and replacing reservoir products,

as wellsas for processing at a minimum cost of equipment, maintenance and operation.

In recent years wells have been drilled to deeper depths and the physical aspects of the gaseous 2U products in the formations show a considerable change in character from the gaseous products normally in the more shallow pools. Among the most prominent of these changed characteristics of the deeper pools is the presenceof some ..5 of the petroleum fractions, generally called dis- F tillates, in a vaporous form and in increasing amounts as compared to the shallower pools, probably due to the higher sub-surface temperatures and pressures prevailing in the deeper for- When these fractions or products are converted or changed into a liquid phase, they may be approximately water-white in color, or in some instances may be more or less colored, and are generally known in the oil fields as dis- 3!) tillates.

Since the xed gases in these relatively deeper pools, and vaporous products, ale both in a common phase under sub-surface reservoir conditions, they are, therefore, not separable While in 4U place in the reservoir under ordinary or control- 4;, common reservoir.

For economic reasons, certain of the products are in demand and may be readily marketed when recovered, and such products are usually those which can be converted by condensation, lique- 59 faction, absorption, or other means, into a liquid phase. From this it follows that there may remain products which, for economical reasons, are not marketable or are not in current demand, and such products usually take the form of residual 55 gas. To avoid the wasteful release of such gas,

Rossuml or other products, into the air or otherwise, it has been found feasible and practical, under certain conditions, to return the residual gas to a subsurface reservoir, or to the source from which it was produced.

In the ordinary process or method of producing the vaporous products from the reservoir or bottom of the Well, a certain amount of condensation from the vaporous form to the liquid phase usually occurs during the passage or transit of the gaseous fluids up the well from thebottom to the top, whether the means of conducting the fluids be through the casing of the well, or

l through the tubing, or both. Such condensation results primarily from the temperature change or m drop which naturally takes place during the passage of the fluids from the high temperature horizon or zone at the base of the well through the progressively lower temperature horizons or zones upwardly toward the surface of the well. The condensation also is brought about by heat exchange, due to the ow of the warm vaporous products through the cooler casing and earth horizons vencountered as the passage continues upward in the well.

When these products arrive at the surface they.

are, therefore, produced at a temperature usually considerably lower than their temperature at the base of the well bore. However, under common practice, the amount or quantity of liquids which is condensed during this passage is only a portion of those liqueflable fractions which could be condensed, were the process of heat exchanging and cooling to continue in the same manner or proportion. Due to the limitation of the natural heat exchange which, as above stated, takes place between the bottom of the well and the surface of the well, it becomes desirable to mechanically continue the process of heat exchanging at the surface, or to employ some other method to fully recover the liqueable fractions from the vaporous products. It has been found economical and practical to recover, by an improved method, additional liqueable products which remain in vaporous form because of the reasons above stated, and this is one of the objects of the invention; however, while the method is particularly applicable to the types of Wells which have been described and are commonly known as distillate wells, there are many other types of wells producing gaseous uids, as well as liquids, and containing liquefiable hydrocarbons,

which are in such quantities as to make it protable to use this method to recover such hydrocarbons.

nomically practical to use methods of the mineral seal type under usual conditions, at high pressures, and particularly where the residual gas is returned to the sub-surface reservoir.

The process or method of recovering the nonrecovered fractions present in vaporous form or liquid phase, and remaining in the well fluids after the natural condensing of the liquefiable fractions by the transit of well fluids upwardly in the well, may be accomplished by using certain of a number of hydrocarbons as a densifying and liquefaction liquid. However,l either the native liquid recovered from the well stream, or an quivalent having kindred characteristics, is used in our improved method, as best suited for the results sought. A

It is, therefore, one of the objects of the method to separate the natural or native liquids which are to be recoverd from the well fluids, or otherwise acquire them, and admix or introduce or inject the same or equivalent liquids, in

a suitable manner or by suitable means, into the well fluids or the well stream, or the gaseous fluids of the well streams, at a desired point either in the upper end of the Well, or on the surface, at some suitable stage in the method or system which may be in advance of a separating step, or between separating steps, or before final segregation of the liquids and gases. The admixture or introduction of these natural or native or other suitable liquids into the well uids or well stream, in any of the ways set forth, serves to increase the liquid content of the fluids being treated to promote recovering therefrom additional native liquids. 1

A further object of -the invention is to provide an improved method, wherein the liquid and vliquefiable components of distillate range in the well stream or well uids are brought into more intimate contact and the liquid content of such stream is increased, by theintroduction of a native liquefaction liquid having substantially the same components as the liquid and liqueable distillate fractions of said stream. By the `introduction of such a liquefaction liquid in suflicient quantities and the consequent increase of the liquid content of the flowing stream, the liquid surface exposed for contact with the liquid and liqueable fractions of the well stream is such that adequate surface is provided for the contact and collection of the desired distillate products of the said stream. The surilcial area exposed for contact of the liquids of the well stream is increased or decreased in accordance with the quantity of the liquefaction liquid introduced and the liquid content is likewise increased or decreased.

Still another object of the invention is to provide an improved method of the character described wherein the recovery of liqueflable fractions of distillate range from well fluids may be carried out by admixing with such fluids a liquefaction liquid of the character described in advance or prior to a separating step; also a method whereby the liquefaction liquid may be introduced or admixed after a separating step or between separating steps; which variations of the method having the advantage of increasing the recovery of ascertained liquids in a practical and profitable manner and in increasing amounts without contaminating the well fluids being treated with foreign substances during the recovery steps, and also producing a residual gas capable of economic processing and requiring only minimum compression for introduction into a sub-surface reservoir.

A particular object of the invention is to provide an improved method for recovering well liquids of the character described which includes admixing with the well stream or well iiuids, quantitiesy of the native or natural liquid of distillate range and in excess of the normal distillate content of the well stream, whereby contamination of the recovered liquids with either a foreign liquid or a blending liquid or .some other substance which either changes the recovered liquid from its natural components in the well or makes additional separation or distillatio/n necessary, is prevented. So long as the liquefaction liquid has the characteristics herein; set forth it may be acquired from any y suitable source, but it is preferably and probably more economical to provide the same by utilizing quantities of the recovered liquids. In this latter event, it is desirable to accumulate the recovered liquid in such volume as to provide ample quantities for recycling the same as the liquefaction liquid. These also, are objects of the invention, as well as the selective controlling and regulating of the supply of liquefaction liquid over a wide range.

Another object of the invention is to provide an improved method whereby the fluids may be produced under well pressures, and the method performed without altering or reducing the wellhead pressure, thus making it possible to carry out the steps at relatively high pressures for the purpose of saving gas, as well as for economic compression in order to raise the gas pressure to a degree suitable for return to a sub-surface reservoir. The advantage of this method resides to a great extent in the conservation of natural resources, whereby waste of the gaseous uids is prevented.

A very important object of the invention is to provide an improved method involving the introduction into or the admixture with the well stream or well fluids of a cool liquefaction liquid of the character described, whereby the liquid content of the well stream is increased and the temperature thereof is reduced at a single step, thus making for increased liquefaction of the entrained liqueable fractions in vaporous form, and utilizing heat exchange, as well as relatively high pressures; permitting control of the gas-to-liquid ratio and reducing atomization; and also affording highly profitable liquid recovery without resorting to sub-normal temperatures, the result being accomplished either by the inherent temperature of the liquefaction liquid or by first cooling said liquid.

A very important object of the invention is to provide an improved method utilizing a liquefaction liquid of the character described which may be pre-cooled, as hereinbefore set forth, 0r which owing to the inherent temperature of the well stream or well iiuids need not be cooled; or wherein the well stream fluids may be cooled prior to the introduction of the liquefaction liquid; lor wherein the well iiuids and liquefaction liquid may be cooled after admixture, any of such procedures producing the desired liquefaction of the liqueable fractions and the advantageous results herein set forth.

A further object of the invention is to provide an improved method for recovering well fluids wherein the composition of the products recovered are controlled by varyingthe rate of introduction of a liquefaction liquid introduced into or admixed with the well stream or fluid, orare controlled by regulating the temperature of the admixture, or by varying the rate of introduction of the liquefaction liquid so introduced, and controlling the temperature thereof at the same time.

Still another object of the invention is to provide a method wherein the well stream flowing from the well is admixed with a liquefaction liquid of the character described and carried through a stage wherein the travel of the well uids and the liquefaction liquid is sufficiently amplified to effect an adequate admixture and consequent recovery of the desired distillates.

'Ihis application is filed as a continuation in part of our co-pending application filed May 26, 1936, Serial No. 81,968.

A construction designed tocarry out the invention will be hereinafter described, together with'other features of the invention.

The invention will be more readily understood from areading of the following specification and by reference to the accompanying drawings, in which an example of the invention is shown, and wherein:

Figure l is a diagrammatical View of an apparatus for carrying out the improved method, in accordance with the invention, and

Figure 2 is a diagrammatical view of another apparatus for carryingout the improved method, in accordance with the invention.

The equipment set forth in Fig. 1 is shown as an illustration of the application of the method to a distillate type of well.

In Figure 1 of the drawings, the letter A designates a well flowing under pressure. It is preferable to employ the method where the wellhead pressure is comparatively high, and of course requires a flowing well or its equivalent.

The well stream is conducted through a pipe B from the well usually without a reduction in pressure, except for the reduction which takes place because of the flow. Where the well-head pressure is very' high, it may be desirable to reduce said pressure by a suitable means, as by valve B'. The well fluids flowing through the pipe B, While having a comparatively high pressure, will usually be largely in vaporcus form, although including liquid phases. Such fluids will generally have a low oil-to-gas ratio.

As set out in the foregoing pages, the character of these distillate wells, to which the method is applicable, is somewhat different than the ordinary oil and gas well, because theV hydrocarbon liquid phase content of the well stream is not only low but the liqueable frac-l,y tions which are sought tobe recovered are predominately in vaporous form and not subject to efficient;4 recovery or separation by ordinary methods now in common use. These wells also usually flow under considerable pressure.

As before recited, it is highly desirable to maintain the flowing pressure within certain limits and permit as littleI pressure-drop as is feasible in carrying out the method. This method involves the recovery of liqueable fractions by increasing the liquid content .of the well fluids through the introduction, or admixture therewith, of a liquefaction liquid, either with or without temperature variations. This method may also involve the control of the temperature .of the wellstream o r well uids together with the admixture of native or equivalent liquids with the well uids for the purpose of increasing the liquid content of said fluids, thus `accomplishing increased surflcial contact and liquefaction of the liquefiable fractions for the subsequent separation of the liquids from the gases. The operation of this method at high pressures is advantageous since lthe degree of atomization or dispersion `of liquid particles, prevailing under these conditions, is reduced-to considerably less than would be the case if the admixture and subsequent separation were carried out at relatively low pressures.

Although the liquefaction liquid may have a lower temperature than the well stream o-r well fluids, at the point of introduction, it is not necessary to resort to extremely low or sub-normal temperatures for eiiicient liquid recovery. Not only is a reduction in the temperature of the well fluids secured by the heat exchange resulting from the contact of the components themselves, when the cool liquefaction liquid is introduced, but such introduction or admixture increases the liquid mass of the well fluids.

Many types of devices may be employed for introducing or injecting the liquefaction liquid into the well fluids or for admixing the same while under pressure. A container or tank C, has proven very satisfactory. The pipe B enters the tank at one side near the bottom. The interior of the tank may vary according to the conditions of operation and there may be baffles C or any other suitable equipment for enhancing the mixing or heat exchanging, or both, by amplifying or prolonging the travel path of the admixed fluids.

The feed pipe D enters the lower portion of the tank for supplying the liquefaction liquid. This method, as before stated, involves the use of a liquid which, While preferably the nativeor natural Vliquid of the well stream, may be an extraneous liquid of the character described and which may be retained with the liquids as finally recovered. No extraneous liquid, such as a foreign oil, mineral seal oil for instance, can be used with this method, because such mediums either change the components of the recovered liquid o1' must be separately extracted at a greatly increased expense.

The character of the recovered liquid products I may be controlled to a great extent by regulation of the temperature within the tank C, or by the quantity of the liquefaction medium introduced thereinto. A hand valve D is connected in the pipe D for controlling the supply of the liquefaction liquid. This pipe extends to the coil E of a cooler-or heat exchanger F of suitable construction. The coil is connected with the force pump G, whereby the liquid is delivered to the tank at a pressure suitable to insure its entrance into the same for circulation therethrough.

A supply pipe H extends from a high pressure separator J to the pump and is connected with a supply pipe I. The pipe H includes a valve H' between the separator and the pipe I, while the pipe I includes a valve I'. If native liquid is used the valve 1' is closed, the valve H opened, and said liquid is supplied from the separator; whereas if extraneous liquid is used, the valve H is closed, the valve I' is opened, and the liquid is lto supplied from a suitable source through the pipe I.

If desired, the valve D' may be closed and the liquefaction liquid or recirculation liquid may be introduced into the pipe B in advance of the tank C through a pipe N, which includes a valve N'. If this latter step is followed, the admixing of the liquefaction liquid in the well stream will bring about a temperature change in the stream prior to entering the tank C, however, as before pointed out, it is possible to introduce the liquefaction liquid into the well stream without causing a temperature change.

A discharge pipe K leads from the top of the tank to the separator. The liquefaction medium will thoroughly admix with the well ulds while ilowing upwardly therewith through the tank C. The said admixing of `the liquid with the well fluids will cause a liquefaction and precipitation of the liqueable fractions which are in vaporous form, by its intimate or surcial contact therewith, thus making it possible toI increase the recovery of the liqueable fractions from the well ilulds.

Ordinarily, the primary well stream of these distillate type wells is substantially composed of free gases not subject to appreciable liqueiaction, fractions in vaporous form which are liqueable, and other fractions in the liquid phase. 'I'hese components prevail in a state in which the liquid phase fractions are highly dispersed or atomized and form a more or less homogeneous mixture with the gases and liqueable vaporous fractions.

In the process of admixing, a major change in the character of the well stream fluids takes place in the form of an increased liquid content which results in a unification of the highly atomized or dispersed liquid particles in the primary well stream uids with the more massive liquid particles of the liquefaction liquid. During this step, in which the unification of the atomized and more massive liquid particles takes place, the resultant liquid and gas admixture is prepared for separation, which is eillciently accomplished due to the fact that the atomized or highly dispersed particles have united or combined with the more massive liquid particles of the medium. During the process of admixture any cooling of the uids which may take place will further increase the recovery of liqueable fractions from the combined fluids. The uids enriched by the liquefaction liquid flow from the tank C, under substantially high pressure, out through the pipe K. This stream ilowing through the pipe K has a much greater liquid content or liquid to gas ratiol than the well stream as it flows from the well and enters the high pressure separator J, preferably at midheight, wherein separation of the liquids from the gas takes place. The pipe K includes valves K', which may be control or regulating valves, or any other kind of valves suitable for use in this method.

The Well stream or iluids having been prepared for separation prior to their entrance into this separator J will yield to separation therein, the liquids descending to the lower portion of the separator, and the gases rising and passing out through the pipe L, which includes a pressure control valve L'. The recovered liquids are discharged through the outlet pipe M which includes a control valve M which may be either of the manually operated type or of the automatically operated type. Any portion of such liquids may be bled oi through the pipe H for use as a liquefaction liquid. The liquid discharged through the pipe M requires no further treatment and is ready for use, ordinarily as a commercial product.

It is pointed out that by regulating the operation of the pump G the quantity and rate of introduction of the liquefaction liquid into either the tank C or the pipe B may be controlled. At some stages in the practice of the method, it may be desirable to employ more or less quantities of liquefaction liquid in order to procure the most eilcient recovery of liqueable fractions. Thus the provision of an ample supply of the liquefying liquid is most desirable and, of course, such liquid may best be used after the separation of the gases therefrom.

It will be obvious that the lean or denuded gas discharge into the pipe L at the top of the separator J will usually be only slightly lower in pressure than the pressure of the owing well ilulds entering theA tank C. If the gas is to be returned to a sub-surface reservoir, its pressure usually should be kept as high as possible for this purpose. It is evident that if the pressure of the well stream or fluids is considerably reduced during a recovery method, then more compression is required in order to raise the pressure of the -residual gas for input purposes. 'I'he method herein recited involves recovery of the liqueable fractions with minimum pressure loss throughout the system, thus making it possible to greatly reduce the cost and operation of compression equipment required for returning gas to reservoirs under high pressures.

As hereinbefore pointed out, our method may be used with other than Wholly distillate type Wells, and some of these other types of wells may produce more or less oil, as well as vaporous form fluids containing liqueable hydrocarbons of distillate range which are in sucient quantities to make it profitable to recover. We have illustrated in Figure 2 equipment for performing the method with these types of wells. In this figure, the numeral I designates a well flowing under pressure from which the well iluids are conducted by a pipe II through a choke II. 'I'he choke is, in turn, connected with one end of a ilow line pipe, or conductor I2. By means of the choke, which is adjustable, the ow of the well stream from the pipe II to the line I2 may be `readily controlled. A T I3' is connected in the line I2 and a valve I3 is interposed in said line between the T and choke. In case it is not desired to pass the well stream through the choke the valve I3 may be closed and said stream carried through a by-pass line I3a. which has one end connected to the T I3 while its other end is connected in-a T I'I a in the line II. When this line I3a is not being used it is closed by a valve I3b. The other end of the flow pipe I2 leads into a separator I4 which may be of any desired construction, according to the nature of the products being handled, and a mixer I5, which may be similar to the tank C of Figure 1 as will be explained, is connected in the pipe I2.

The type of well to which the equipment shown in Fig. 2 is applied produces 'with the gaseous fluids, liquid of lower volatiles than distillates, and these lower volatiles must of a necessity, be recovered, either by separation or some other methods, from the' gaseous iluids prior to extraction of the distillates from the said gaseous uids. However, after primary separation there is usually present in the gaseous fluids large quantities of distillates which must be separately recovered. Therefore, by .introducing the well stream or well uids into the separator I4, the

liquid low volatile hydrocarbons present in such suitable pump 30.

iiuids or stream as it iiows from the well are separated from the gaseous nuids which contain the recoverable liquefiable fractions of distillate range.

'I'he residual liquids recovered in the separator I4 may be conducted to a storage tank I6 by an outlet pipe I1, which pipe has a control valve I8 connected therein. This valve may be operated either automatically or manually. It is to be noted that the characterfof the liquids flowing from the separator 'may vary to a great extent and, of course, will depend upon the nature of the liquids of the well stream.

The liquids which are separated in the separator I4 may be conducted to the storage tank I6, or other disposition may be made thereof. A T I9 is connected in the pipe I1 in advance of a valve 26, which may be closed to cut off the iiow to the tank I6. A pipe 2| leads from the T and includes a cutoff valve 22.

By closing the valve 26 and opening the valve 22, the liquids may be conducted to a T 23, which is connected to a manifold 24, which, in turn, is connected to stock tanks 25. Suitable control valves 24 are located in the manifold 24 adjacent each tank 25 and ycontrol the flow of liquid into the tanks. From the above, it will be evident that by manipulating the valves 20 and 22 the liquid recovered in the separator I4, may be conducted either to the storage tank I6 0r the stock tanks 25.

In some instances, it may be desirable to utilize the liquids separated in the separator I4 as a liquefaction liquidand introduce or inject the same into the well stream or well fluids in ad- Vance of the separator I4. For this purpose, a second outlet pipe 26 having a valve 21 connected thereinleads from the lower end of the separator. The outer end of this pipe is connected to a T 28 and a short pipe 29 leads from the T to a The outer side of the T 28 has a pipe 3i extending therefrom and the opposite end of this pipe leads to the storage tank I6. A suitable valve 32 is connected in the pipe 3l. With this arrangement, the pump may be supplied with liquid either direct from the separator through the pipe 26 or from the storage tank I6, or from both. It might be desirable to vsupply the pump with an extraneous liquid and for this purpose an inlet pipe 33 leading from a suitable source of supply is connected to the pump 3U. A suitable control valve 34 is connected in said pipe.

The pump 36 forces the liquid through a pipe 36 which has a pressure gauge therein, whereby the pressure of the liquid being pumped may be determined. In place of the pump, any suitable means may be used for propelling the liquid and placing it under a desired pressure. The other end of the pipe 36 is connected to a T 31 which `T is connected in the flow line I2 between the mixer I5 and valve I3, whereby the liquid is pumped into the flow in advance of the separator. The pipe 36 includes a control valve 38 located adjacent the flow line and a pressure vgauge 31. A suitable-heat exchanger 39 is located in the pipe 36 and is so arranged as not to interfere with a. free passage of the liquid when not in operation. The exchanger may be utilized to heat the liquid or to cool it, and its purpose, when used, is to bring the liquefaction liquid to the proper temperature. Many conditions, such as l seasonal changes, climatic variations., and tem- -the liquids are separated from the gaseous uids.

These separated liquids may be carried to the storage tank I6 or the stock tanks 25, or both; or they may be conducted to the pump, either from the separator I4 or tank I6, or both, for recycling as a liquefaction liquid. When conducted to the pump, they are forced into the pipe 36 and introduced into the ow line I2. When so introduced, it is of course necessary that the liquefaction liquid be placed under sufilcient flowing pressure to enter the owing well fluids. The introduction of the liquefaction liquid will increase the liquid content of the well fluids, as has been explained, whereby liqueiiable fractions present in vaporous form in said fluids are accumulated and united with the liquids entrained in said fluids. The admixed well iluids and liquefaction liquid iiowing through the pipe I2 pass into and through the mixer I5, which latter could also be the tank C of Figure 1. While the mixer or tank may be, in some instances, omitted, it is desirable to use the same in order to obtain a more intimate mixture of the components of the gaseous fluids and liquids flowing therethrough. Under some conditions, it may be desirable or advantageous to connect a heat exchanger 40 in the pipe I2 between the mixer and separator I4 and use the same in conjunction with, or independently of, the exchanger 39; however, the exchanger 40 may be omitted entirely.

When the liquefaction liquid is introduced into the line I2, as above explained, liqueiiable fractions are accumulated and subsequently separated in the separator from the gaseous uids, passing off with the liquids. If the recycling of the liquids recovered in the separator is not desirable, then it is only necessary to close the valves 21, 32, and 38 in the pipes 26, 3|, and 36 respectively, and open the valve I8 in the outlet pipe I1, whereby the separated liquids may be conducted to the tank I6 or stock tanks 25.

The gaseous iiuids of the Well stream, which are separated from the liquids in the separator I4, are conducted therefrom by a flow line 4I which leads from the upper end thereof. These gaseous iiuids usually contain liqueable fractions which are not recoverable in the separator. The iiow line 4I has connected therein, in the order named, a valve 42, a `T 43, a mixer 44, which may be similar to the mixer I5, a T 45 and a valve 46. The other end of the line 4I leads into a tank 41, which may be a separator, accumulator or stabilizer. A pipe 48 including a valve 49 is connected to the T 45, whereby any of the gaseous iiuids flowing through the line 4I may be taken therefrom for any purpose.

From the above, it is manifest that the gaseous iiuids are conducted from the separator I4 to the tank 41. The liquids which are recovered in this latter tank may be taken therefrom through an outlet pipe 50 which has a valve 5I connected therein. The outer end of the pipe 50 is connected to a T 52 which is, in turn, connected to a manifold 53 leading to stock tanks 54. The manifold includes suitable control valves 53' for controlling the flow into said tanks. Y

In order to recover the liqueflable fractions present 'in the gaseous fluids flowing through the line4|, itis desirable to recycle as a liquefaction liquid quantities of the liquids which have been recovered in the tank 41. For this purpose, a. second outlet pipe 55 leads from the tank 41 to a suitable pump 56, similar to the pump 30. A suitable valve 51 is connected in the pipe 55. For supplying an extraneous liquefaction liquid of the character described in connection with Figure 1, a supply pipe 58 including a valve 59 is connected to the pump 56. 'Ihis extraneous liquid may or may not be supplied, as desired.

The pump forces the liquefaction liquid supplied thereto through a pipe 60 which has its other end connected to the T 43 in the flow line 4| in advance of the mixer 44, whereby the liquid is introduced into the flowing gaseous fluids. The pipe 60 has a pressure gauge 6|, as well as a heat exchanger 62, similar to the exchangers 39 and 40, connected therein. As is Vthe case of the exchangers 39 and 40, the exchangers 62 and 63 may or may not be used.

The liquefaction liquid introduced into the flow line 4I will admix with the gaseous fluids flowing therethrough and the liquef'lable fractions of distillate range will be accumulated so that upon their introduction into the tank 41, these liqueflable fractions will be recovered as liquids. The gaseous fluids and the liquefaction liquid introduced thereinto will pass through the mixer 44 and will be thoroughly admixed before their entrance into the tank. If desired, a heat exchanger 63, similar to the exchangers 39, 40, and 62 may be connected in the line 4| between the mixer 44 and T 45.

With the above arrangement, it will be seen that the gaseous fluids which are separated from the liquids of the well stream in the separator I4 may be admixed with a liquefaction liquid prior to their entrance into the tank 41, whereby the liquefiable fractions present in said fluids are recovered as liquids. The liquefaction liquid may be quantities of the liquids recovered in the tank 41, or such liquid maybe extraneous, being supplied through the pipe 58.

It is pointed out that the system herein described is very flexible for by manipulating the various valves, the well stream may be admixed with a liquefaction liquid prior to a separting step or after an initial separation of liquids and gaseous fluids; or the well fluids may be treated both before and after a separating step. In all cases, the liqueable fractions normally present in vaporous form are economically recovered.

The residual gas Whichis separated from the liquid in the tank 41 is substantially denuded of liquefiable fractions and is discharged from said tank through a pipe 64 which has a valve 65, either manual or automatic, connected therein. The gaseous uids which are discharged from the separator I4 into the pipe 4| or from the tank 41 into the pipe 64, are under pressure, which may vary but which usually will be comparatively high. Within certain limits and ranges, this pressure may be maintained and controlled and, therefore, excessive and wasteful pressure losses or drops may be avoided. This is highly desirable, particularly for economic reasons, where the gas is to be compressed to raise its pressure for injection into input Wells, as well as for other reasons.

The pipe 64 is connected with the inlet manifold 66 of a compressor unit 61. The discharge manifold 68 of the unit connects with a pipe 69 which, in turn, is' connected with one or more branch pipes 10 leading to input wells 1|. It is pointed out that the pipes 10 are broken to indicate thatthe input wells are `preferably remote. A service pipe 12j including a valve 13 also extendsfrom the pipe 89 for conducting the compressed gas therefrom for other purposes. When the gas is not to be compressed, a T 14 is connected in the gas discharge line 64 and a pipe 15 including a valve 16 leads from said T. By`

conducting the gas from the pipe 15, said gas may be returned to a sub-surface reservoir having a less pressure than the pressure of the reservoir of the well I0. In such case, compression is not necessary.

It is to be noted that under some conditions the best results may be obtained in this method where the quantity of liquefaction liquid introduced is greater, or many times as great, as the recoverable liquid content of the well fluids flowing from the well at the point of introduction; however, the method is not to be limited either to the amount or proportion of the liquefiable liquid introduced or its rate or point of introduction.

As used herein, the terms well fluids and well stream mean the fluids produced by the well, irrespective of their treatment or disposition. 'I'he term fluids is generic and refers to liquids, vapors, gaseous uids and so called gases.

The term vaporous form as used herein, is intended to cover all fluids having the form of vapors, mists or gaseous uids. The term recovered liquids, liquids recovered, liquid recovery, or separated liquids, may be applied to the liquids which are normal-1y present in the well stream either in liquefiable form or in liquid form and which are accumulated, recovered or separated at some stage in the method; and may also include the liquefaction liquid which is added.

By the term liquid content, is meant either or both liquid and liquef-lable fractions present in the well stream. 'I'he term liquids of distillate range vcovers both liquids and liquefiable fractions which are classed as distillates and as distinguished from heavy hydrocarbons.

It is pointed out that the invention deals with the recovery of certain products or hydrocarbons classified as distillates and flowing from the well in vapor form or as liquefiable fractions. It is the purpose to precipitate these fractions and recover them as native liquids without adulterating them. 'I'he invention seeks to avoid admixing with the native well gases or liquids, when treating such gases, any blending liquid, foreign liquid or heavier hydrocarbon. The liquefaction liquid should not contain any components which are not within the range of the liquids to be extracted from the gaseous fluid. Therefore, it is prefer able, but not necessary, to accumulate the recovered native liquid and recycle it as the liquefaction liquid. It is also true that there may be produced with the gaseous fluids, quantities of water vapors, which may condense during the riperation of the method and this water may be drawn olf. Possibly some of this naturally present water may still remain in the liquefaction liquid when recycled, but it is to be understood that the presence of such water is not necessary to the performance of the method.

'Ihe term distillate or distillates" or of distillate range, as applied in this application, refer to the recoverable products of high A. P. I. gravity range, produced from the so-called distillate wells and from oil wells which produce a agosassl" separable liquid and a gaseous fluid, from which the separable liquid may be primarily extracted by co ventional oil and gas separation, and the disti late `or high A. P. I. gravity liquids are later recovered from thel gaseous fluid which has been separated from the crude oil and are of such components that they come within the scope of the so-called distillate or distillates or of distillate range as applied in our method. However, no present nomenclature has been found on the term above applied except the general and common oil country terminologies above recited when referred to such wells, and in some cases these same wells are commonly called water white wells, or water white distillate wells, and these same wells and products are often referred to as such in trade and other publications for the oil industry. The invention is not to be construed as intended to include the recovery of all and every hydrocarbon of the well stream, but as directed to the recovery of certain well products of distillate range.

What we claim and desire to secure by Letters Patent, is:

1. The method of recovering natural distillate products from wells producing such products in gaseous form which includes, conducting the well stream containing said natural distillate products from a well flowing under high pressure, admixing with the gaseous fluids of the well stream at a temperature not in excess of the natural maximum temperature of the well stream, a liquefaction liquid having substantially the same composition as the natural distillate liquids to be recovered from the gaseous well stream and in such quantities as to produce in the admixture a total liquid content in excess of the normal amount of such natural components contained in said well stream, said liquefaction liquid being introduced in the form of relatively large particles so as to minimize atomization thereof and the formation of mist, concurrently fiowing the admixed fluids while subjected to amplified surflcial contact whereby natural distillate liquid particles of such size and weight as to induce precipitation and increased liquid recovery are agglomerated with the liquefaction liquid, and separating the gas from said liquid particles to recover the natural liquids.

2. The method of recovering natural distillate products from wells' producing such products in gaseous form which includes, conducting the well stream containing said natural distillate products from a well owing under high pressure, admixing with the gaseous fluids of the well stream at a temperature not in excess of the natural maximum temperature of the well stream, a liquefaction liquid having substantially the same composition as the natural distillate liquids to be recovered from the gaseous well stream and in such quantities as to produce in the admixture a total liquid content in excess of the normal amount of such natural components contained in said Well stream, said liquefaction liquid being introduced in the form of relatively large particles so as to minimize atomization thereof and the formation of mist, concurrently flowing the admixed fluids while subjected to amplied surcial contact whereby natural distillate liquid particles of such size andweight as to induce precipitation and increased liquid recovery are agglomerated with the liquefaction liquid, separating the gas from said liquid particles to recover the natural liquids, and recycling portions of thel recovered distillate liquids and utilizing said recycled liquids as the liquefaction liquid; l.

3. The method of recovering natural distillate products from wells producing such products in gaseous form\ which includes, conducting the well stream containing said natural distillate products from a well flowing under high pressure, conducting the well stream through a separating stageto remove extraneous hydrocarbons and liquid products, flowing the residual well stream containing the natural distillate well products to be recovered from the separating stage under high pressure, admixing with the gaseous uids of the well stream at a temperature not in excess of the natural maximum temperature of the well stream, a liquefaction liquid having substantially the same composition as e natural distillate liquids to be recovered from the gaseous well stream and in such quantities as to produce in the admixture a total liquid content in excess of the normal amount of such natural components contained in said well stream, said liquefaction liquid being introduced in the form of. relatively large particles so as to minimize atomization thereof and the formation of mist, concurrently flowing the admixed fluids while subjected to amplified .surflcial contact whereby natural distillate liquid particles of such size and weight as to induce precipitation and increased liquid recovery are agglomerated with the liquefaction liquid, and separating the gas from said liquid particles to recover the natural liquids.

4. The method of recovering natural distillate products from wells producing such products in gaseous form which includes, conducting the well stream containing said natural distillate products from a well flowing under high pressure, admixing with the gaseous fluids of the well stream at a temperature not in excess of the natural maximum temperature of the well stream, a liquefaction liquid having substantially the same composition as the natural distillate liquids to be recovered from the gaseous well stream and insuch quantities as to produce in the admixture a total liquid content in excess of the normal amount of such natural components contained in said well stream, said liquefaction liquid being introduced in the form of relatively large particles so as to minimize atomization thereof and the formation of mist, concurrently fiowing the admixed uids while subjected to amplified surficial contact whereby natural distillate liquid particles of such size and weight as to induce precipitation and increased liquid recovery are agglomerated with the liquefaction liquid, separating the gas from said liquid particles to recover the natural liquids, and recycling and cooling portions of the recovered liquids and utilizing said recycled liquids as the liquefaction liquid, whereby the admixing of the liquefaction liquid with the gaseous Well stream is carried out at a relatively low temperastream. a liquefactionliquid having substantially `and in such quantities as to produce in the admixture a total liquid content in excess of the normal amount of such natural components contained in said well stream. said liquefaction liquid being introduced in the form of relatively large particles so as to minimize atomization thereof and the formation of mist, concurrently flowing the admixed ulds While subjected to amplified suriicial contact whereby natural distillate liquid particles of such size and weight as to induce precipitation anddncreased liquid recovery are agglomerated with the liquefaction liquid, and separating the gas from said liquid particles to recover the natural liquids.

6. The method of recovering natural distillate products from wells producing such products in gaseous form which includes, conducting the well stream containing said natural distillate products from a Well flowing under 'high pressure, admixing with the gaseous fluids of the well stream at a temperature not in excess of the natural maximum temperature of the Well stream, a liquefaction liquid having substantially the same composition as the natural distillate liquids to be recovered from the gaseous well stream and in such quantities as to produce in the admixture a total liquid content in excess of the normal amount of such natural components contained in said well stream, said liquefaction liquid being introduced in the form of relatively large particles so as to minimize atomization thereof and the formation of mist, concurrently flowing the admixed fluids through a prolonged travel path and under constant turbulence while subjected to amplified suraosasi iicial contact whereby natural distillate liquid particles of such size and weight as to induce precipitation and increased liquid recovery are agglomerated with the liquefaction liquid, and separating the gas from said liquid recover the natural liquids.

7. The method of recovering natural distillate products from wells producing such products in gaseous form which includes, conducting the well stream containing said natural distillate products from a well owing under high pressure, admixing with the gaseous fluids of the well stream, at a temperature not in excess of the natural maximum temperature of the well stream, a liquefaction liquid having substantially the same composition as the natural distillate liquids to be recovered from the gaseous well 'stream and in such quantities as to produce in the admixture a total liquid content in excess of the normal amount of such natural components contained in said well stream, said liquefaction liquid being introduced in the form of relatively large particles so as to minimize atomization thereof and the formation of mist, concurrently ilowing the ad-I mlxed iiuids while subjected to amplified surcial Contact whereby natural distillate liquid particles of such size and weight as to induce precipitation and increased liquid recovery are agglomerated with the liquefaction liquid, separating the gas from said liquid particles to recover the natural liquids, and recycling portions of the recovered distillate liquids as the liquefaction liquid and varying the rate of introduction of said liquefaction liquid to control the recovery of the products.

JAY P. WALIiER. EDWIN V. FORAN.

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